Deputy Prime Minister Barnaby Joyce and a string of federal Nationals MPs have criticised the West Australian Liberals for striking a preference deal with One Nation — warning the agreement could cost them power in the state election.

Key points:

Liberals are directing preferences to One Nation in the WA state election

Deputy PM Barnaby Joyce is warning the Nationals may retaliate by running candidates in urban seats

Premier Colin Barnett says the move is purely to keep Labor out of power

The West Australian Liberals have decided to preference One Nation above the Nationals in the Upper House in regional areas, with One Nation preferencing the Liberals in all Lower House seats in return.

WA Premier Colin Barnett has said it is a pragmatic decision aimed purely at keeping Labor out of power.

But Mr Joyce has predicted the move will backfire.

"It's a statement of fact that the most successful governments in Australia are Liberal-National Governments and however that bond is formed it works well. When you step away from that, there's one thing you can absolutely be assured of, you're going to be in opposition," Mr Joyce said.

"This is a disappointing move. I hope the architects of it clearly understand the ramifications of the decision that they're a party to."

One Nation leader Pauline Hanson said the deal demonstrated her party was gaining stature and influence.

"They've got no choice but to take me seriously. The primary vote for both major political parties is on a downer. So they know to shore up and try to get themselves back into Parliament and into the government it's with One Nation's preferences," she said.

But Mr Joyce also warned the WA Nationals might be tempted to retaliate in the future by running candidates in urban seats.

"The game could be played in any way — we won't, but it could easily be that the National Party could stand in every Lower House seat in Perth and preference another party. What would that mean? You'd lose a heap of seats, as simple as that," he said.

"Colin Barnett has been around the political game a long while. He should seriously consider whether he thinks this is a good idea, or whether he's flirting with a concept that will ultimately put his own side, his Liberal colleagues, in opposition."

Deal angers Nationals heavyweights in Canberra

The Liberals and Nationals in Western Australia have a more antagonistic relationship in Western Australia than they do in the eastern states.

The two parties are in power together, but they do not govern in a formal coalition.

But the deal has still angered Nationals heavyweights in Canberra, who are increasingly concerned about the electoral challenge that a resurgent One Nation poses in regional areas.

Nationals MPs lined up to criticise the WA Liberals as they entered parliament house this morning.

"[The Liberals] will need the National Party if they're going to have a hope of forming government, and always remember who your friends are," Victorian Nationals MP Andrew Broad said.

"It seems a bit desperate I've got to say and when you go and make friends with people who don't share the same values of you, it makes it very hard to form a government."

Nationals MP Mark Coulton also questioned the deal.

"I don't know whether it's all that smart of a move. The Nationals have done an amazing job. The Royalties for Regions, they've really stood up for the bush, so I wouldn't think that the One Nation would be in the ascendency in a lot of those places," he said.

Decision is for WA Libs, Turnbull says

Finance Minister and Western Australian Liberal powerbroker Mathias Cormann brushed off the criticisms — pointing out the Nationals had previously preferenced One Nation and several other minor parties ahead of the Liberal Party.

"In 2013 both the Liberal Party and National Party preferenced the Shooters and Fishers, the Christian Democrats and the Family First party ahead of each other. This is just business as usual," Senator Cormann said.

Prime Minister Malcolm Turnbull also dismissed questions about the deal, saying it was a decision for the Liberal Party in Western Australia.

"They've got to make their judgement based on their assessment of their electoral priorities. Their objective you've got to remember is to persuade people to vote Liberal and return the Barnett Government," he said.

Former prime minister Tony Abbott told Sydney radio station 2GB that if he was making decisions on preferences he would be "putting the National Party ahead of everyone".

"The National Party are our Coalition partners in Canberra and in most states, and they're our alliance partners in Western Australia. So as I said, One Nation above Labor and the National Party above everyone. That would be my approach," Mr Abbott said.

Mr Abbott was a fierce critic of One Nation in the late 1990s and early 2000s — and Senator Hanson accused him of bankrolling the court cases which led to her brief imprisonment for electoral fraud in 2003.

Senator Hanson served 11 weeks before the conviction was quashed.

Labor's Anthony Albanese said there was no comparison between Labor's decision to preference the Greens and the Liberals preferencing One Nation.

"There's a big difference between the Greens political party and the views of people like Bob Brown and others who I disagree with and the views of Pauline Hanson," he said